Avionics

Index
» Topic Specific Forums (COO membership required)
» Avionics
» Sharing an Altitude Encoder?

Page: 1

Post tools
- Subscribe

Sharing an Altitude Encoder?

2009-11-04 02:24:09

Sharing an Altitude Encoder?

Does anyone know if an altitude encoder can supply a signal to more than one device (transponder and GPS).

I am working on acquiring parts to upgrade my panel. I currently have a VFR only apollo 2001 gps that i plan on replacing with a GX50 that will be configured for IFR enroute and approach. I have acquired all of the major components with the exception of an altitude encoder. I currently have a narco 150 transponder with altitude encoding, so i know that i have either a stand alone encoder or an altimiter with built in encoding.

I'm trying to find out if the encoder is capable of supplying both the transponder and the GPS with the RS-232 input. If it is capable, is a special splitter or adaptor needed to split or amplify the signal?

Thanks for any help.

theoneon: 4 Posts

Only registered users or members can reply or post

2009-11-06 20:51:41

Re: Sharing an Altitude Encoder?

The Narco 150 is already connected to the by Grey Code wiring from the encoder. If the encoder has an RS-232 port available (up to 4 or 5 devices can be paralleled) you can use that for the GX50 GPS. If no RS-232 is available, you can parrallel the grey code lines; the GPS has internal isolation diodes to allow that. Be very careful parralleling the grey code lines, it is very easy to get these lines mixed up, which will cause some very interesting altitude data being sent to the transponder and/or the GPS.

Guest: Guest; Posts

Only registered users or members can reply or post

2009-12-03 21:39:52

Re: Sharing an Altitude Encoder?

Do NOT parallel multiple receivers onto an RS232 output!

The RS232 standard will drive only one reciever per output.

You may parallel quite a few devices onto ICAO altitude outputs, up to the limit of the encoder's output driver. Refer to your encoder's specifiation sheet. Beware of cross talk issues, and verify all receiving devices are diode isolated.

If you need more RS232 formatted outputs you can use an altitude encoder with multiple RS232 outs or get a repeater, Trans-Cal makes one.